1. Field of the Invention
The present invention relates to a fine particle measuring method, a substrate for fine particle measurement, and a fine particle measuring apparatus. More specifically, the present invention relates to a fine particle measuring method capable of controlling the timing of emission of light to sample fluidic channels into which fine particles are introduced.
2. Description of the Related Art
In order to distinguish fine particles, such as biological fine particles including cells, microorganisms, and liposomes, or synthetic particles including latex particles, gel particles, and industrial particles, apparatuses that introduce fine-particle-dispersed liquid into fluidic channels and optically measure the fine particles introduced into the fluidic channels have been used in the related art.
As an example, there is a particle analyzer that distinguishes synthetic particles according to the size or shape. The particle analyzer measures the element composition or diameter of a fine particle and the number of particles by exciting and emitting fine particles in helium (He) plasma one by one to perform spectral detection of the fine particles.
Moreover, for the biological fine particles, optical measurement using flow cytometry (flow cytometer) is widely performed. The flow cytometry is a technique of measuring the size or structure of a fine particle to be measured, such as a cell or a microbead, by making the fine particle flow to the middle of laminar flow of sheath liquid in a flow cell, irradiating light onto the fine particle by means of an optical detection unit, and detecting scattered light or fluorescence generated from the fine particle.
In recent years, a microchip for performing such optical measurement of a fine particle within a fluidic channel provided on a substrate formed of glass or plastics by using fine processing technology in a semiconductor industry is under development.
An analysis system using such a microchip is called a μ-TAS (micro-total-analysis system), a lab on chip, or a biochip and has been drawing attention as a technique of enabling an improvement in the speed of optical measurement of a fine particle, integration, or miniaturization of a measuring apparatus. In the case of the μ-TAS, applications to biological analysis of a precious micro sample or many samples are particularly expected since an analysis using a small amount of samples is possible or disposable use of a microchip is possible.
JP-T-2005-538727 discloses a microchip (refer to a particle sorting system 1700 of FIG. 17 in the document) for performing optical measurement and sorting of fine particles in fluidic channels. The particle sorting system 1700 includes a plurality of sorting modules 1701 (sample fluidic channels) operating in parallel. In the particle sorting system 1700, a sample is introduced from an input region 1710 into each sorting module 1701 and predetermined characteristics of particles are measured simultaneously in a detection region 1720. Thus, high-speed measurement and sorting of particles are realized.